This disclosure relates to the die bonding of semiconductor chips to ceramic or metals, and more particularly, to die bonding of semiconductor chips to semiconductor packages using a gold die bond sheet preform.
Die bonding of semiconductor chips to packages or headers typically involves metalizing the semiconductor package with gold alloy and bonding of the die to the substrate. Die bonding is of critical importance for power devices, for example, that require a high quality die bond to dissipate heat from the package, and, in some cases, provide a low impedance interface between the bottom of the die and the die bond area.
For the package manufacturer the amount of gold plated on to the semiconductor package is an important factor in the cost of the package. The thickness of the gold layer on the package must be enough to provide a secure bond surface for the die attach process. In addition, variations in die types by the same manufacturer when the die is manufactured affects die bond.
Therefore, it can be appreciated that a package that require less gold than conventional packages while still maintaining a comparable level of performance is highly desirable.
Further, a package in which the thickness of the gold at the die bond area can be easily adjusted to accommodate variations in die types and other features is also highly desirable.